1. Importance of MySQL User Management

1.1 What is MySQL User Management?

MySQL user management is the cornerstone of database security and operation. Databases often contain sensitive information, making proper user management essential to prevent unauthorized access. By granting specific privileges to each user and allowing only necessary operations, you ensure data protection and system stability.

1.2 Situations Requiring User List Confirmation

Confirming the user list is particularly important during security audits and user management tasks. For example, when adding new users or changing existing user privileges, reviewing the current user list helps check for unnecessary users or identify potential privilege issues. Furthermore, during troubleshooting, checking who is connected from which host makes it easier to pinpoint the root cause of a problem.

2. Location of MySQL User Information

2.1 Overview of the mysql.user Table

In MySQL, user information is stored in the user table within the mysql database. This table contains extensive information about users, including username, host, authentication plugin, and password expiration details. By querying this table, you can retrieve detailed user information.

2.2 Permissions to Access the mysql.user Table

Accessing the mysql.user table requires special privileges. Typically, only the root user or users with the SELECT privilege on this table can access it. This restriction prevents regular users from viewing information about other users, thereby ensuring database security.

3. Methods to Retrieve the User List

3.1 Basic Query to Get the User List

To retrieve the user list, use a query that selects the Host and User columns from the mysql.user table. Execute the command as follows:

SELECT Host, User FROM mysql.user;

This query allows you to view all users in the database and the hosts from which they can connect.

3.2 Explanation of the Execution Results

The query results display a list of user and host combinations. The Host column shows the hosts from which the user can access, and the User column shows the username. For example, if `localhost` is displayed, that user can only access from the local machine.

4. Checking Detailed User Information

4.1 Retrieving Passwords

To check detailed user information, execute a query from the mysql.user table that includes the Password column:

SELECT Host, User, Password FROM mysql.user;

This query retrieves information including the user’s encrypted password.

4.2 Importance of Encrypted Passwords

The retrieved passwords are encrypted. This is crucial for maintaining security. If passwords were not stored in an encrypted state, the risk of unauthorized access by malicious users would increase significantly. Therefore, password encryption is fundamental to database security.

5. Checking User Authentication Information

5.1 Checking the Currently Connected User

To check the currently connected user in MySQL, use the user() and current_user() functions. These functions return the username at connection time and the actually authenticated username, respectively.

SELECT user(), current_user();

Typically, both functions return the same value, but they may differ in cases of anonymous users or specific authentication configurations.

5.2 Importance of Authenticated Username and Hostname

From a security perspective, the actually authenticated username and hostname are important. By accurately grasping this information, you can clearly verify which user is accessing the database from which host. This is useful for security audits and detecting unauthorized access.

6. Checking Settings During User Creation

6.1 How to Use the SHOW CREATE USER Command

To check how a specific user was created, use the SHOW CREATE USER command. This command displays the SQL statement used to create the specified user.

SHOW CREATE USER 'username'@'hostname';

This command allows you to check detailed creation settings, such as the user’s authentication method and password settings.

6.2 Example: User Creation Settings

For example, to check the creation settings for a user like tanaka@localhost, execute the command as follows:

SHOW CREATE USER 'tanaka'@'localhost';

This will display information such as which authentication plugin the user is using and how password expiration and security requirements are configured.

7. Checking User Privileges

7.1 Checking User Privileges with the SHOW GRANTS Command

To check the privileges set for a created user, use the SHOW GRANTS command. This command displays all privileges granted to the specified user.

SHOW GRANTS FOR 'username'@'hostname';

Executing this command will display a list of privileges granted to the user.

7.2 Importance of Privilege Management and Best Practices

Managing user privileges is a critical component for maintaining database security. By properly setting privileges, you prevent unnecessary operations and protect data integrity and confidentiality. The root user, in particular, has powerful privileges, so its use requires significant caution. Granting only the minimum necessary privileges to regular users and reviewing them periodically is a security best practice.

8. Conclusion

8.1 Key Points of MySQL User Management

Confirming and properly managing the user list in MySQL is fundamental to database security. By retrieving user information from the mysql.user table and checking user authentication information and privileges, you can enhance system security.

8.2 Next Steps in User Management

Once you have confirmed the user list, consider reviewing privileges and deleting unnecessary users as a next step. Additionally, implementing stronger password policies and conducting regular audits can further improve database security.

9. References and Resources

 
• MySQL Official Documentation: MySQL 8.0 Reference Manual

 

• Security Related Books: “How to Build Secure Web Applications Systematically” (Author: Hiroshi Tokumaru)